1. Field Of The Invention
The present invention is directed to an automated process of taping joints between adjacent pieces of wallboard and an automated apparatus for effecting such taping of the joints. More particularly, the present invention is directed to an automated process and apparatus whereby a superior finished joint between adjacent pieces of wallboard may be completed in one step.
2. Description Of The Prior Art
Wallboard (also known as drywall) has become the dominant material in the production of interior building partitions. In particular, interior building partitions generally comprise a studwall of spaced parallel vertical members (studs) which are used as a support for preformed panels (wallboard) which are attached to the studwall by screws, nails, adhesive or any other conventional attachment system. Obviously, joints exist between adjacent preformed panels In order to provide a continuous flat surface to the wall, it is necessary to "finish" the joint between adjacent panels Generally, such "finishing" requires the building up of multiple layers of a mastic material (joint compound) and the blending of this joint compound into the panel surface so as to form the desired flat and contiguous wall surface. In order to facilitate this finishing of the joints, most manufacturers bevel the longitudinal edges of the wallboard panels so as to allow a buildup of mastic material which will then match the level of the major surface area of the preformed panel. Typically, the buildup of the mastic material in the joint area comprises the application of a first layer of mastic material, the embedding of a wallboard tape (for example a paper tape or a fiberglass tape) in the first layer of mastic material and then the overcoating of the tape with one or more, generally two layers of additional mastic material. This finishing of the joints is a time consuming process, since it is generally necessary to wait 24 hours between each application of a coat of mastic material in order to allow the coat to dry before the application of an overcoat of an additional layer of mastic material. Moreover, it is then necessary generally to sand the joint area so as to produce a finish which will match the major portion of the surface area of the wallboard panels. The "finishing" process thus is both time-consuming and labor-intensive.
In this regard, numerous attempts have been made to speed up and/or reduce the labor involved in the finishing products. In this regard, attention is directed to U.S. Pat. Nos. 2,666,323 and 2,824,442, to Ames, which disclose a tool designed to apply a layer of mastic to a wallboard joint.
U.S. Pat. No. 3,007,837, to Goode, Jr., discloses a tape and joint compound dispensing wallboard taping machine which uses air pressure to supply joint compound to the head of the tool where it is applied to one side of the tape which side of the tape is then applied to the wall.
U.S. Pat. No. 3,131,108, to Kennard, discloses a wallboard taping machine which may have interchangeable e heads (or different conditions, e.g. flat joints versus corner joints.
U.S. Pat. No. 3,343,202, to Ames, discloses a tool for applying mastic to wallboard which includes a swingable arcuate trawling blade.
U.S. Pat. No. 3,404,060, to Taylor, Jr., discloses a wallboard taping machine including a supply of both joint compound and tape. The device includes a tape cutting knife which is automatically retractable and the tape has the joint compound applied on one side thereof.
U.S. Pat. No. 3,707,427, to Erickson, discloses a tape and joint compound dispenser wherein the tape is drawn through a joint compound reservoir so that the joint compound is applied on one side thereof. The quantity of joint compound in the dispensing chamber is automatically regulated.
U.S. Pat. No. 3,880,701, to Moree, discloses a tape and joint applying tool including applicator rolls and a blade for cutting the tape.
U.S. Pat. No. 3,925,145 discloses a tool for embedding tape into mastic at the corner of a room after the mastic and tape have been previously applied to the corner joint of the room.
U.S. Pat. No. 3,960,643, to Dargitz et al., discloses a device to apply a tape and covering finish plaster to a drywall seam in a single pass lengthwise thereover, wherein a relatively lightweight, hand supported frame has a unit thereon operative to first apply glue to a length of tape and then glue-affix the tape to the drywall over the seam and another unit on the frame operative, but trailing the tape gluing and applying unit, the apply a thin, smooth, layer of joint compound over the then-in-place tape.
U.S. Pat. No. 4,080,240 to Dysart, discloses a device for applying tape to wallboard and including valve-controlled mud supply. The device also includes a severing knife and a retractable V-shaped roller.
U.S. Pat. No. 4,086,121, to Ames, discloses a self-contained drywall taper having a hollow elongated body for holding mastic and supports a roll of tape with tape feeding means to deliver the tape to tape applying wheels then in turn apply it to cover a joint between two wallboard sections . A piston is slidably mounted in the hollow body and is automatically moved by a mechanism actuated by the rotating wheels, as they are moved over the wallboard surface, to force a layer of mastic onto the tape just prior to it being applied to the surface.
U.S. Pat. No. 4,090,914, to Hauk et al., discloses an apparatus for applying tape and adhesive to wallboard joints which is then convertible to deposit adhesive over the previously applied tape.
U.S. Pat. No. 4,196,028, to Mills, discloses a joint compound and tape applying tool having the provision of a following corner roller.
U.S. Pat. No. 4,208,239, to Lass, discloses a drywall taping machine including a flexible resilient wiper blade which presses the cement-laden tape into engagement with the wall and, in addition, feathers the cement onto the drywall along both side edges of the tape in a single pass. A backpack support for the joint compound supply is disclosed.
U.S. Pat. No. 4,309,238, to Hauk, discloses a drywall taping device which has a control for adjusting the tensioning force applied to toothed traction wheels thereof.
U.S. Pat. No. 4,358,337, to Johnson et al., discloses a tape applicator which utilizes a replaceable joint compound cartridge system.
U.S. Pat. No. 4,452,663, discloses a wallboard joint taping apparatus including an elongated frame having a tape press wheel mounted on the forward end with a compound reservoir mounted on the frame, intermediate the ends, with aligned slots through the lower edge of the wall with a source of tape mounted on the other end of the frame with the tape passing through the slots in the compound container for picking up taping compound on the surface thereof and passing over the roller for application and pressing by the press wheel into a joint between adjacent wallboard panels.
U.S. Pat. No. 4,516,868, to Molnar, discloses a device designed to apply a layer of joint compound over an already installed length of tape.
U.S. Pat. No. 4,592,797, to Carlson, discloses a tube including a cylindrical roller for applying pressure to embed a tape in adhesive, the roller being designed to allow the mud which is on (he underside of the tape to flow over the top of the tape and coat that surface as well.
U.S. Pat. No. 4,608,116, to Braselton, discloses a baseboard edge taping tool which includes a severing knife and which is specifically designed to enable cutting operations at a corner.
Other references relating to tape dispensing and mastic dispensing include U.S. Pat. No. 2,972,428, to Dubbs, which discloses a tape applicator including microswitch controls for advancing, severing and applying a pressure sensitive tape. Movements of the tape are controlled incrementally on a cyclicable basis.
U.S. Pat. No. 3,785,535, to Ames, discloses a mastic supply pump outlet for filling different types of mastic-applying tools.
U.S. Pat. No. 4,406,247, to Baughman et al., discloses control of the flow of adhesive in an adhesive dispensing system wherein a logic control unit receives signals indicative of various process conditions and in response thereto controls. adhesive dispensing.
U.S. Pat. No. 4,477,304, to Westermann, discloses a tool designed to apply a predetermined quantity of adhesive on a workpiece.
U.S. Pat. No. 4,584,047, to Vanderpool et al., discloses a hand-held labeling device which senses the position of the web of labels and controls other operation in response to this sensed condition.
Despite the great efforts which have been applied to reduce the labor and time involved in wallboard finishing, there is still a marked need for an efficient and useful tool which is easy to operate and which will allow a one-step finishing of wallboard.